Integrated circuits that include a microprocessor require a mechanism by they start up, or “Boot”.
Since they include a programmable microprocessor, such ICs are flexible enough to be designed into a variety of products. However, different products may require the IC to behave in different ways. While the majority of these differences can be accommodated by making changes to software, a mechanism is still needed to load the necessary code into the IC at boot time. Unfortunately this very mechanism may also be application specific. For example, in some applications the boot code may be stored in one of several types of external non-volatile memory chip, while in others the IC may be expected to load its boot code using one of a variety of serial communications links.
It would be advantageous to provide a more flexible, configurable boot mechanism.